The analysis of vitamin B in human milk and colostrum is greatly complicated by the lack of modern methodologies available as well as the large number of B vitamers present in these fluids. This project will develop a radiometric microbiological assay for vitamin B-6 and niacin to complete the development of similar assay procedures for thiamin, biotin, and pantothenic acid in these fluids. Specifically, the project will: 1) apply already developed RMA for vitamin B-6 and niacin for the anlaysis of these vitamins in human colostrum and milk. 2) complete the development and validation of RMA's for thiamin, biotin, and pantothenic acid and apply the RMA's in the analysis of these vitamins in human colostrum and milk.